Tomatine cholesterol

Friedman, M., Fitch, T. E., Yokoyama, W. E. (2000b). Lowering of plasma LDL cholesterol in hamsters by the tomato glycoalkaloid tomatine. Food Chem. Toxicol., 38, 549-553. 

These complex systems are also targets of many natural products (Table IV). Disturbance of membrane stability is achieved by 9-methoxyelliptic-ine, ellipticine, berbamine, cepharanthine, tetrandrine, steroidal alkaloids, irehdiamine, and malouetine. Steroidal alkaloids, such as solanine and tomatine, which are present in many members of the Solanaceae, can complex with cholesterol and other lipids of biomembranes cells are thus rendered leaky. 

CAS 17406-45-0. C H NO. A glycosidal alkaloid prepared from the dried leaves and stems of the tomato plant. White crystals used as plant fungicide and as a specific precipitating agent for cholesterol and other sterols. The crude extract is referred to as tomatin. 

Steroidal alkaloids, such as solanine and tomatine which are present in many members of the Solanaceae, can form complexes with the cholesterol and other lipids present in biomembranes. Important for this interaction is the presence of a lipophilic portion of the molecule (given by the steroidal moiety) and a hydrophilic portion (provided by the sugar side chain). Whereas the lipophilic moiety "dives" into the lipophilic interior of the membrane and interacts with the structurally similar cholesterol, the hydrophilic side chain remains outside and binds to external sugar receptors. Since phospholipids are in a continuous motion (spinning around their axis and horizontal movements), a tension easily builds up which leads to membrane disruption i.e. transient "holes" form in the biomembrane rendering the cell leaky. Since particular steroidal alkaloids can specifically interact with receptors, ion channels or transmitter... 

Figure 5. Effect of pH on binding of tomatine to cholesterol in vitro.

Insects also require an exogenous source of phytosterols (27). The glycoalkaloid tomatine is an effective precipitator of certain phytosterols such as sitosterol and cholesterol, and as such may provide a means of reducing sterol intake for noctuid larvae (97). 

Alkaloids such as solanidine and tomatidine are related to diosgenin in terms of structure. These cholesterol-derived metabolites usually occur as the 3-(7-glycosides (e.g., sola-nine and tomatine) (Mann, 1987) (see Chapter 36). 

Heemann V, Brtimmer U, Paulsen G, Seehofer F (1983) Gomposition of the leaf surface gum of some Nicotiana species and Nicotiana tabacum cultivars. Phytochemistry 22 133-135 Heftmann E (1983) Biogenesis of steroids in Solanaceae. Phytochemistry 22 1843-1860 Heftmann E, Schwimmer S (1972) Degradation of tomatine to 3P-hydroxy-5a-piegn-16-en-20-one by ripe tomatoes. Phytochemistry 11 2783-2787 Heftmann E, Weaver ML (1974) 26-Hydroxycholesterol and cholest-4-en-3-one, the first metabolites of cholesterol in potato plants. Phytochemistry 13 1801-1803 Hegnauer R (1973) Chemotaxonomie der Pflanzen, vol 6. Birkhauser Verlag Basel, Switzerland, pp 420-430 446-449... 

Kabara, j. j., j. T. McLaughlin, and C. A. Riegel Quantitative microdetermination of cholesterol using tomatine as precipitating agent. Analyt. Chem. 33, 305 (1961). 

Huang, T.C., Wefler, V., Raftery, A., 1963. A simphfied spectrophotometric method for determination of total and esterified cholesterol with tomatine. Anal. Chem. 15, 1757—1758. 

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